Installed this tonight. Here are my observations.
The Good News:UPNP vulnerabilities are fixed. Did a scan with grc.com's ShieldsUP! service (
https://www.grc.com/x/ne.dll?bh0bkyd2) and everything came up clean.
The problem with the Guest Zone disappearing that showed up in firmware 2.10NA appears to be fixed. I haven't been running it long enough to be 100% sure, but both WiFi connections appear to be stable.
The Bad News:The wireless client list under Status/Wireless no longer works. This page no longer shows anything no matter how many wireless clients I have connected to the router.
Update: This appears to only be broken in Internet Explorer 9 and Internet Explorer 10. Works find in IE8 and below and Chrome and Firefox.
This appears to be a trend I have noticed in D-Link firmware updates on many of their devices. Newer firmware releases appear to be breaking support in IE9 and IE10 where the older release works fine in those browsers. I have noticed this same trend on several routers and other D-Link devices. I had to return a $200 D-Link wireless security camera because the latest firmware completely broke support for Internet Explorer and the previous firmware release was no longer available for download.